1. Field of the Invention
The present invention relates to a multidirectional operating switch which is driven by tilting or pushing an operating shaft and is used as an input operation section in mobile communication apparatuses such as a portable telephone, a pager, etc., or various electronic apparatuses such as a remote control apparatus, an audio apparatus, a TV game apparatus, a car navigation system, an electronic camera, etc., and also relates to a multidirectional operating apparatus using the same.
2. Description of the Related Art
A conventional multidirectional operating switch will be described with reference to FIGS. 1 to 4.
FIG. 1 is a cross-sectional view illustrating a configuration of the conventional multidirectional operating switch; and FIG. 2 is a partially cutaway exploded perspective view illustrating the same.
The illustrated multidirectional operating switch has a box-shaped case 1 made of a resin, with an opening thereof being covered by a cover 2 made of a metal plate, or the like. As shown in FIG. 2, central fixed contacts 3A and 3B (also indicated generically by reference numeral 3) and four peripheral fixed contacts 4 to 7 are fixed by the insert molding on the bottom surface of the case 1. The peripheral fixed contacts 4 to 7 are provided along the periphery around the center of the location of the central fixed contact 3 so as to be equally spaced apart from one another. The fixed contacts 3 to 7 are connected respectively to terminals 14 to 18 for connection to an external circuit.
A dome-shaped movable contact 8 is placed on the outer contacts 3A of the central fixed contact 3. On the other hand, resilient contact members 10 to 13 of a common movable contact member 9, which is secured by dowels 1A, are placed on the peripheral fixed contacts 4 to 7, respectively. The resilient contact members 10 to 13 are connected via a contact 19 to a terminal 19A for connection to an external circuit.
Compression coil springs 20 are arranged along the inner periphery of the wall of the case 1. The compression coil spring 20 biases a supporting member 21 upwards so that an upper end portion 21A thereof elastically contacts the lower surface of the cover 2.
A dent portion 21B is provided at the center of the supporting member 21, so as to hold a hemisphere rotation member 22. A flange portion 22A around the lower periphery of the rotation member 22 is placed on the bottom surface of the dent portion 21B provided at the center of the supporting member 21. An upper spherical surface portion 22B is in contact with a spherical circular hole 2A of the cover 2 so as to fit therein. Moreover, a rod-like operating shaft 23 made of a metallic material is fitted and held in a non-circular central vertical hole 22C of the rotation member 22 so that it can move vertically.
A lower end portion 23A of the operating shaft 23 extends downwards past the rotation member so as to be in contact with the dome-shaped movable contact 8 provided at the center of the bottom surface of the case 1. On the other hand, an operating knob 24 is attached to a tip portion 23B of the operating shaft 23 which extends upwards out of the case 1.
Moreover, pressing portions 25A to 25D are provided on the peripheral portion of the lower surface of the supporting member 21 so as to correspond respectively to the resilient contact members 10 to 13 of the common movable contact member 9.
Hereinafter, the operation of the conventional multidirectional operating switch having such a configuration will be described further referring to FIGS. 3 and 4 as well as FIG. 1. Each of FIGS. 3 and 4 is a cross-sectional view schematically illustrating a certain operation state of the conventional multidirectional operating switch.
In the state shown in FIG. 1, the operating shaft 23 is in the vertical and neutral position, with the lower end portion 23A thereof not pressing down the dome-shaped movable contact 8. In this state, connection between any pair of the contacts is in the OFF state.
When an end of the knob 24 (the left end in the example illustrated in FIG. 3) is pressed down as indicated by an arrow in FIG. 3, the operating shaft 23 is tilted, and the rotation member 22 rotates to the left while being in contact with the spherical circular hole 2A of the cover 2. Thus, the end portion of the flange portion 22A on the lower surface of the rotation member 22 presses down the bottom surface of the dent portion 21B of the supporting member 21, and the supporting member 21 is tilted to the left about a fulcrum at the upper end portion 21A on the side of the square opposite to the side of the pressed surface. Thus, the resilient contact member 10, which corresponds to the pressing portion 25A, is pressed down so as to contact the corresponding peripheral fixed contact 4. This turns ON the connection between the common movable contact member 9 and the peripheral fixed contact 4 so as to supply a signal to the outside through the terminals 19A and 15.
At this point, a portion of the peripheral upper end portion 21A of the supporting member 21 which is located on the left in FIG. 3 comes off the lower surface of the cover 2 while compressing downwards the compression coil spring 20. Thereafter, when the force being applied to the knob 24 is removed, the supporting member 21 and the rotation member 22 are pushed back to the original neutral position by virtue of the restoring force of the compression coil spring 20. Moreover, the resilient contact member 10 comes off the peripheral fixed contact 4 and back to the original position (see FIG. 1) by virtue of the resilient restoring force thereof, whereby the switch contact is turned back to the OFF state.
As described above, by pressing down the upper surface of the knob 24 at a certain point thereof, a signal is supplied from the switch to the outside through one of the terminals 16 to 18 which corresponds to the pressed position (direction).
Moreover, when the operating shaft 23 is pressed down by vertically pressing down the central portion of the upper surface of the knob 24, i.e., the operating shaft 23, as indicated by an arrow in FIG. 4, the lower end portion 23A of the operating shaft 23 presses down the dome-shaped movable contact 8. This inverts the dome-shaped movable contact 8, thereby generating a click while turning ON the connection between the central fixed contact 3 (between 3A and 3B), and a signal is generated and supplied to the outside through the terminal 14.
When the force being applied to the knob 24 is removed, the operating shaft 23 is pushed up by virtue of the restoring force of the dome-shaped movable contact 8 so as to be back in the original position as shown in FIG. 22.
However, while there has been a strong demand for downsizing various electronic apparatuses, the conventional multidirectional operating switch having such a configuration is too large in terms of outer diameter and thickness, and will not satisfy such a downsizing demand. Moreover, the number of components is large, and the cost is high.
Furthermore, a click is not generated when a switching operation is performed by tilting the operating shaft 23, whereby the switching operation cannot be ensured by a feel.